Sterilization technology is absolutely essential for our daily life. For example, it is used for water and sewerage system, foods, and medicine. Methods widely used for sterilization use drug, heating, ultraviolet (UV) radiation, and ozone. Chlorine is used extensively in sterilization because of its easiness and low cost. Using chlorine has some adverse effects such as alteration of quality of the target. Also it is bad for environment discharge water sterilized by drug to rivers and oceans. Conventional methods for UV sterilization use UV lamps. These are used to sterilize workspaces and tools used in biology laboratories and medical facilities. Low pressure mercury-vapor lamps emit 254, nm wavelength of UV which coincides very well with peaks of the germicidal effectiveness curve (i.e., effectiveness for UV absorption by DNA). Low pressure mercury-vapor lamps contain mercury and it has harmful effects to the environment and human body.
There are many systems that use ultraviolet light. Some systems are designed to generate effects such as fluorescing effects while other systems are used for the purification of objects, liquids and vapor.
Water purification systems are in great demand for industrial, home, portable, and other uses. These systems are designed to purify a predetermined quantity of water before dispensing for consumption or other use. There are many techniques or methods used to purify water. Usually, multiple techniques are employed within one purification device. Filters are generally used to remove particulates from the water while ultra-violet light is used to disinfect the water. The disinfection process may involve passing water through a clear tube while passing ultraviolet light through the tube simultaneously. The ultraviolet radiation is used to eliminate most bacteria and viruses.
UV light disinfects water by permanently deactivating organisms such as bacteria, spores, moulds, viruses or the like. Light having wavelengths between 200, nm and 300 nm, also known as UVC, is known to be responsible for this effect. This application of UV sterilisation in aquatic environments such as ponds or aquariums is also known.
However, UV lamps and tubes have relatively high power consumption. UV lamps and tubes also degrade over time and eventually become ineffective for water treatment making replacement necessary. This adds significantly to the costs of UV water treatment, both because of the relatively high cost of the new tubes, and because of the frequency of replacement. Furthermore, UV degradation is not immediately obvious to an observer. Hence, treatment lamps and tubes are often used for a long time after they become ineffective.
Although the sterilization technology using UV is a traditional method, development of efficient and low cost sterilization equipment is still lacking.
Also air contamination, particularly indoor air contamination, contributes to human health complications. Specifically, airborne chemical and/or biological contaminants, particularly when present in poorly ventilated areas, cause a wide variety of human illnesses. Biological contaminants include bacteria, fungi, fungi spores, protozoa, viruses, algae, pollen, various antigenic agents, and the like, and are known to cause such health complications as pneumonia, fever, mycotoxicosis, various infections, asthma and the like. Prior art air sterilization devices suffer from a number of problems. First, the devices are large and consume significant amounts of useable space in an office or home environment. Second, though they may provide a means for reducing airborne contaminants, they do not address the odors that may be present in the areas of intended use. In addition, the prior art devices are very inefficient. More often than not, they require an associated volume of air in the area of intended use to be recirculated multiple times through the device in order for the contaminants to be effectively removed.
WO2010071814A1, discloses a system for disinfecting a fluid. The system includes a flow cell with inlet and outlet ports, configured to communicate a fluid containing a biological contaminant from the inlet ports to the outlet ports through an interior portion thereof. The flow cell wall is provided with apertures and point radiation sources are disposed in these apertures. The point radiation sources are described to be UV optical sources, deep-UV optical sources, semiconductor optical sources, and/or LED optical sources. They are operable for delivering radiation to the biological contaminant. The interior surface of the flow cell reflects the radiation delivered by the point radiation source(s) such that a radiation intensity is uniform throughout the interior portion of the flow cell. The flow cell can be an integrating sphere or an integrating ellipsoid.
WO2007113537A1, discloses a treatment apparatus for at least partially disinfecting a fluid such as water comprising a pipe for conveying a flow of fluid to be treated, a series of ultraviolet (UV) light emitting diodes (LEDs) for emission of UV light into the fluid, and a control circuit for controlling operation of the LEDs. The pipe has apertures extending from the outer surface to the inner surface of the pipe and the UV LEDs are placed in the apertures. The aperture are sealed for fluid impermeability such that the fluid flowing in the tube, in operation, does not leak out of the pipe through wall. Electrical circuitry for operation of the LEDs is located on a flexible printed circuit board (PCB) wrapped cylindrically around the pipe. The apparatus also includes sensors which can for example monitor the level of UV or natural light passing through the fluid.
The prior art does not utilize UV LED point radiation sources emitting light through apertures sealed in the ends with a UV transparent material, and there is no indication that the flow cell is toroidal-shaped with an inner concave parabolic surface.
It is an object of the present invention to overcome one or more of the aforementioned problems in removing and/or generally reducing the presence of air or water borne contaminants in an efficient manner. In particular, there is a need for a flow cell with improved disinfection of a fluid to be treated.